This invention relates to a writing instrument having a pocket clip and an ink cartridge which are each retractable into the pen body by actuating a pushbutton.
U.S. Pat. No. 3,101,075 discloses a writing instrument, having a clip made in one piece with a pushbutton. In the barrel of the writing instrument, a guide groove extending at an angle to the longitudinal axis is associated with the pushbutton. Upon actuation, the pushbutton and also the clip made in one piece therewith not only move in the direction of the longitudinal axis but also transversely of the longitudinal axis. Furthermore, a control unit comprising an upper annular element and a lower annular coupling element is provided separately from the pushbutton. By depressing the pushbutton the clip can be pushed laterally out of the barrel, and after the pushbutton is released, the margin of a pocket or the like, for example, can be gripped between the clip and the barrel. The clip is operated exclusively by means of the pushbutton. In order to retract the ink cartridge into the barrel, the tip of the ink cartridge is pressed against a hard surface, while an axially displaceable sleeve at the front end of the barrel is pushed back into the interior of the barrel. This shifts the coupling means into a rest position. To extend the ink cartridge out of the barrel, the sleeve and the tip of the ink cartridge are again pressed upon a hard surface thereby actuating coupling parts of a cam, so that the ink cartridge is shifted to the writing position. In the retracted position the tip of the cartridge is close to the front end of the writing instrument, but its distance away from it cannot be easily increased since the maximum movement of the ink cartridge is determined by the shapes of the cam and the coupling parts, and by their axial length. Furthermore, even when the cartridge is extended, the writing instrument can be fastened to an article of clothing, with the danger that the clothing may be stained by leaking writing fluid. The clip can be extended out of the barrel by actuating the pushbutton regardless of the position of the ink cartridge.
Another writing instrument is disclosed in German Patent No. DE 30 46 093, which has a clip arranged so as to be retractable into an opening in a barrel. The operating unit comprises a pushbutton and a control or operating cam for holding the cartridge in the writing position or in the position in which it is retracted into the barrel. At the upper end of the clip there is an operating head which engages the opening in the barrel on the one side, passes through the barrel, projects from the barrel on the side opposite the clip, and there has an exposed operating surface. The cartridge is extended from the barrel by pressing the pushbutton which protrudes from the upper end of the barrel, causing the clip to retract such that on the opposite side the operating head with its operating surface protrudes from the barrel. In the writing position, the pushbutton, and hence the cartridge, is held by means of a guide projection which is disposed on the operating head, and which snaps into a locking surface provided at the upper end of the cam. To retract the cartridge back into the barrel a user must act upon the operating surface to press the operating head projecting from this side of the barrel radially inwardly toward the longitudinal axis of the barrel, releasing the guide projection from the locking surface and, on the other side, shifting the clip out of the barrel. The locking surface and the guide projection are subjected to relatively great stress and wear. Arranging the cam above the end of the cartridge for the actuation of the cam creates corresponding bulk. To operate the cartridge a user must act at two different points, namely at the pushbutton at the upper end of the instrument to deploy the cartridge and at a lateral operating surface of the operating head to retract it. This makes operation inconvenient. In writing, the operating head with its operating surface protruding laterally from the barrel can be disadvantageous, and accidental retraction of the cartridge may occur when handling or putting down the writing instrument, or even while writing with it.
French Patent No. FR 22 25 298 discloses a writing instrument in which the clip is a component of the pushbutton. In this writing instrument too, when the clip is actuated, it moves both in the direction of the longitudinal axis and transversely of the longitudinal axis. No additional information is found in this disclosure about the design of a guide cam or operating cam.
German Utility Model No. DE-U 72 44 435 relates to a writing instrument having a clip and a writing part which can be deployed to a writing position and retracted to a rest position. Here the clip is disposed substantially within the circumferential limits of the barrel of the writing instrument. The writing part is deployed and retracted by means of an actuator which is configured as a pushbutton at the rearward end of the barrel. The clip is connected to the actuator by a resilient swivel connection. The clip and the actuator consist of a single piece, and the resilient swivel connection is achieved by the shaping and the elasticity of the material.